Chicago tech companies saw some big C-level shakeups in 2015. Two of the city’s pillar tech companies–Groupon and GrubHub–made moves to hire new executives. Acquisitions brought new talent to Braintree and Raise. And Chicago startup Uptake landed two big hires as the company continues its explosive growth.

To get a sense of the companies that shook things up last year and are preparing for a big 2016, we’ve listed the Chicago tech companies that made crucial hires in 2015.

Rich Williams
Groupon CEO Rich Williams (via Groupon)

Rich Williams–Groupon

In what was probably the most notable Chicago tech CEO shakeup of 2015, Rich Williams was named the chief executive of Groupon in November. The former Groupon COO replaced Eric Lefkofsky, the company’s co-founder who replaced Andrew Mason as CEO in 2013. Williams, who joined Groupon in 2011 as the Senior Vice President of Marketing, is charged with turning around the deals giant–which at one point was the world’s fastest growing company.

Barbara Martin Coppola–GrubHub

GrubHub landed a big hire in May when it named Barbara Martin Coppola as its chief marketing officer. Coppola came to Chicago from Silicon Valley where she held several marketing leadership roles at Google. Before joining GrubHub she was the head of marketing for Google’s same-day delivery service Google Express, and she also led marketing efforts for YouTube and Chromecast.

Harper Reed–Braintree/PayPal

Harper Reed, the former CTO of Obama for America and Threadless, sold his latest startup Modest to PayPal in August. Modest, a company that allows retailers to easily embed “buy” buttons in their own apps, became part of Braintree, which was acquired by PayPal for $800 million in 2013. Reed is now the head of commerce at Braintree and a senior director of software development at PayPal where he’s helping to define the future of commerce at the payments giant.

NuCurrent Director of Product Engineering Glenn Riese (via NuCurrent)

Glenn Riese–NuCurrent

Fast-growing Chicago startup NuCurrent, a company that’s developing wireless power antenna technology for mobile devices, announced in May that it hired Glenn Riese, a former Motorola Mobility engineer. Riese worked at Motorola from 1994 to 2014 and played a vital role in developing the RAZR and the Droid, two of the company’s most iconic products. Riese was named NuCurrent’s director of product engineering, and he heads up design and development of NuCurrent’s wireless power applications.

Tyler Spalding–Raise

Tyler Spalding’s startup Tastebud Technologies built apps for malls and shopping centers to help send relevant discounts and notifications to in-store shoppers. Tastebud was acquired by Chicago gift card marketplace startup Raise in August, and will help Raise deliver digital gift cards to users in-store. Spalding was named Raise’s chief strategy officer as part of the acquisition.

Greg Goff
Uptake Chief Product Officer Greg Goff (via LinkedIn)

Greg Goff–Uptake

In December, Fast-growing Chicago startup Uptake landed a high-profile hire in Greg Goff, the former CTO at Morningstar. Goff is now the chief product officer at Uptake and will be charged with shaping the technology roadmap for the young startup–which is already valued at more than $1 billion.

Sonny Garg–Uptake

Goff wasn’t the only big time hire for Uptake in 2015. The startup named Sonny Garg, the former chief information officer at Exelon, to its roster in July. Garg is leading Uptake’s energy solutions team, where he’s using Uptake’s Internet of Things technology to change the energy industry.

Adrienne Weissman–G2 Crowd

In February G2 Crowd, the Chicago-based platform for software reviews, hired former LinkedIn executive Adrienne Weissman as the company’s chief marketing officer. Weissman spent three years at LinkedIn as the director of marketing solutions, working with brands like Microsoft, FedEx, and Ford to help them leverage LinkedIn as a content marketing and advertising platform. She now leads the sales and marketing efforts at G2 Crowd and is in charge of increasing traffic to the site’s thousands of software reviews.

Katy Lynch
Techweek CEO Katy Lynch (via Techweek)

Katy Lynch–Techweek

Katy Lynch was named the CEO of Techweek during a tumultuous time for the Chicago-based traveling tech conference after it sent out what many deemed to be a sexist email promoting its “Black Tie Rave Event” in 2014. Lynch, who was the founder and CEO of Social Katy, a social media marketing agency that was acquired by Manifest Digital, was tasked with improving the organization’s reputation, and growing the startup in the US and globally. Since she was hired, Techweek has expanded to Cuba, and this week it announced plans to bring the conference to Toronto and Dallas.

Kenneth Fuchs–STATS

Chicago-based sports tech company STATS scored a big hire in November when it named former Yahoo executive Kenneth Fuchs as its new chief executive officer. Fuchs spent almost two years as global Vice President at Yahoo, where he led Yahoo Sports, Yahoo Finance, Yahoo Entertainment and strategic partnerships. And he worked last year on the historic NFL livestream of the Bills vs. Jaguars game that was shown elusively on Yahoo and seen by more than 15 million people.